Concentrated fish press liquor



Patented Oct. 10, 1950 CONCENTRATED FISH PRESS LIQUOR James K. Gunther,Decatur, Ind., and Louis Sair, Evergreen Park, Ill., assignors toCentral Soya Company, Inc., Fort Wayne, Ind., a corporation of IndianaNo Drawing. Original application January 12,

1946, Serial No. 640,998. Divided and this application August 26, 1948,Serial No. 46,368

4 Claims.

This invention relates to a concentrated fish press water product. Theapplication constitutes a division of our co-pending application, SerialNo. 640,998, filed January 12, 1946, now Patent 2,454,315, for Processfor Treating Fish Press Water.

Fish press water is a by-product of the fish processing industry. Thebody fiuids are pressed from the fish and the resulting press water iscondensed to varying extents, but usually to a point where it containsapproximately 50% solid matter. Such press water contains valuablevitamins and supplements for feeds.

Since fish press water has to be shipped for considerable distances topoints where it is to be incorporated in various feed products it is ofgreat importance to increase the concentration as much as possible. Anincrease in concentration much beyond 50% has been found impracticable,however, because of the tendency of the concentrated material to gel,forming a tough gelatinous material which cannot be handled until thematerial is again made fluid by heating at higher temperatures.

Another problem confronting the industry is that of preserving thematerial against putrefaction or spoiling. The water has a. fishy odor,is somewhat adhesive, and when stored at the usual commercialconcentrations at temperatures of 70 F.-140 F. tends to become putrid.An increase in concentration greatly aids in preserving the material,but such increase in concentration has been prevented heretofore by thegelling characteristic of the material. In order to attempt to preventspoiling, acid is usually added to bring the pH below 5.5. While suchlowering of the pH at times is an aid in delaying putrefaction, it is byno means reliable inasmuch as decomposition frequently occurs at pHvalues of 5.5 and lower.

Another difliculty in the handling of fish press water or condensed fishsolubles is caused by the viscosity and varying viscosities of thematerial. These viscosities make it difiicult to properly meter thepress water and to incorporate it uniformly with a feed material. Suchviscosities are afiected not only by the gel factor, but also by thepresence of suspended solids and oil in the material.

An object of the present invention is to provide a concentrated fishpress water product which may be shipped at low cost from the coastalareas to interior points where it may be incorporated in feeds. Afurther object is to provide a highly concentrated fish press waterwhich does not require the low pH heretofore found necessary forpreservation and which may be kept with a satisfactory degree ofstability and with a minimum of treatment for prolonged periods. A stillfurther object is to provide a concentrated fish press water havingincorporated therein minute amounts of proteolytic enzyme for the.-effective removal, for practical purposes, of the gel factor and forviscosity reduction. Otherspecific objects and advantages will appear asthe.

specification proceeds. I

We have discovered that the gel factor, which:

has prevented the concentration of condensed. fish solubles or fishpress water to the degree desired with good fluidity at temperatures of.45-100 F. can be effectively overcome by the use of a relatively smallamount of a proteolytic: enzyme. Any proteolytic enzyme may be em--ployed for this purpose as long as the operation is Within the operablepH range of the particular enzyme employed. Papain has been found to beparticularly useful for effectively overcoming the gel characteristicsof the press water for the temperature ranges usually encountered, andthis enzyme is also desirable because it may be employed at a pH of4.55.5.

We have also discovered that an important infiuence upon the viscositiesof the material encountered in practice is the presence of suspendedsolids and oil in the material. Our process contemplates a method forthe removal of such solids and oil so that a uniform distribution of thevitamin and protein supplement material can be obtained within the bodyof the material and its effective use in the incorporation with feedsprocess at the fish processing plants because of" the substantial savingin freight costs effected through the shipment of highly concentratedimaterial inland to the feed-mixing plants.

The proteolytic enzyme may be used with fishpress water of widelyvarying solids content. It; has been used with concentrated fishsolubles;

and with fish press Water having less than 18% solids.

after the papain or other enzyme has been stirred.

A relatively short treatment is sufficient... andconcentration of thematerial may be beguninto the mixture for a matter of an hour or so andafter the pH has been brought into the operable pH range of the enzymeselected.

We find that all proteolytic enzymes may be successfully used providedthe pH is maintained in the operable pH range of the particular enzymeused, but some of the enzymes are found to be more effective thanothers. Since, however, so little of the enzyme is necessary to bringabout the important new results, the efficiency of the particular enzymeis of minor importance, and the cost differential is not great. Weprefer, however, to use papain not' only because of its unusually highefliciency but because it operates well within the pH range of 4.5-5.5,arange that is desirable from the standpoint of requiring less change inthe material as it is received.

The percentage of papain employed maybe varied widely. Concentrations ofpapain varying from 0.1-0.01% have been used with good results as havealso some concentrations of papain below 0.02%. A specific example ofthe use of papain may be set out as follows:

10.0 pounds of condensed fish solubles containing 18% solids (14.4%dissolved-3.6 suspended) were brought to a pH of 5.0 and the temperaturewas raised to 110 F. 0.01 %of papain was added (0.082 gram to 815 gramsof solids in the condensed fish solubles) and stirring was continued for1.5 hours. The papain treated liquor was then concentrated in vacuo to52% total solids. The viscosity of a sample was determined at 75 F., 60F., and 45 F. and the evaporation was continued to 60% total solids.Again v'iscosities were determined and the solids were then raised to70% by further evaporation. The relative viscosities' are shown in thetable.

It can be seen that whereas the control sample (no papain treatment) wasquite viscous at 60 F. and a solid at 45 F. the treated material wasreadily fluid at all temperatures including 45 F;' Sample No. 3 whichwas concentrated to 60% solids was even more fluid over the temperaturerange than was the control.

In our preferred process, We first remove the suspended solubles and oilfrom the fish press water by any suitable method. This removalisaccomplished satisfactorily by centrifuging, and we prefer to carry oncentrifuging operations at a temperature from 17 -185 F. If the cornme'rcial concentrated product is beingtreated, it is important to firstdilute the material to reduce the solids content from 50% to a muchlower:

percentage, as, for example, to 20% solids. In this operation, we" areable to remove from 80-90% of the suspended solids in the com-mercialcondensed fish solubles product (dry sub- 4 stance basis). Besidesremoving the suspended solids, the centrifuging permits the recovery offrom 5.1-7.7 of fish oil (D. S. basis). We prefer to carry on thecentrifuging operation to an extent where l'essthan 10% of the originalsuspended solids and oil remains in the material.

The product obtained by the above centrifuging operation may beconcentrated to a higher degree than was possible prior to suchcentrifuging and the viscosity of the product is substantially less. Inthe removal of the solids, we are removing an inactive material in thesense that it does not contain to any substantial extent the" desiredvitamin or growth-promoting supplements. The removal of the solidsfurther reduces the viscosity of the material, and thereby the gellingcharacteristics While, at the same time preventing sedimentation duringstorage. Similarly, the removal of the oil definitely reducesviscositywhile at the same time there is no substantial loss in the activematerial desired for promoting growth, etc. Further, the removal of theoil carries with it the cause of disagreeable odors which are undesiredin the final product.

After the centrifuging operation which has removed most of the suspendedsolids and the oil, the pH is lowered to the operating pH range of theenzyme employed and the enzyme is stirred into the mixture to an extentto bring about its thorough incorporation in the mixture. A temperature'is maintained suitable for the operation of the enzyme for a shortperiod of time and then concentration may proceed until the materialcontains more than 74% solids.

- The final product containing in excess of 74% solids is found to havemuch less tendency to decompose and can bestored for long periods oftime without change.

The concentrated material remains highly fluid at low temperatures, andthere is no need for heating apparatus to be employed at thevarious-plants except in rare instances of very cold weather for raisingthe temperature of the product so that it may be handled in bulk as afluid of regulated viscosity both during storage and upon application ofthe material to feeds.

' While in the foregoing description we have set forth specific samplesand specific details of procedure, it will be understood that suchdetails may be modified widely by those skilled in the art withoutdeparting from the spirit of our invention.

We claim:

1. A concentrated fish press water of relatively low viscosity andconsisting of fish press water havinga solids content of at least 50%and a proteolytic enzyme. p

2. A concentrated fish press water of relatively low viscosity andconsisting of fish press water having a solids content of at least 70%and a proteolytic enzyme.

3. A concentrated fish press water of relatively low viscosity andconsisting of fish press water having a solids content of at least 50%and papain.

4. A concentrated fish press Water of low viscosity and consisting offish press water having a solids content of at least 50%, and from .01to .l% of papain.

JAMES K. GUNTHER. LOUIS SAIR.

No references cited.

1. A CONCENTRATED FISH PRESS WATER OF RELATIVELY LOW VISCOSITY ANDCONSISTING OF FISH PRESS WATER HAVING A SOLIDS CONTENT OF AT LEAST 50%AND A PROTEOLYTIC ENZYME.